Linux task scheduler: cron. The file in which tasks to schedule are defined is crontab.
You can either run all three blocks as a normal program (if they're in the same source file) at scheduled intervals, or put the three blocks in separate files (to create three distinct executables), and place all three in the crontab.
However, crontab's smallest interval is one minute, so you might want to write a quick shell script that includes the three blocks, and place the script in the crontab.
A simple pseudocode example:
This will constantly execute the three programs. Keeping them running is a different story.
Also, if you use this method (writing a script and placing it to run every minute or something) you probably want to add lines to kill any already-running instances of the three programs, so you don't end up with infinite programs (adding an instance of the script each minute will eventually cause problems).